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Publications in Scientific Journals:

B. Scheichl, R. I. Bowles, G. Pasias:
"Developed liquid film passing a smoothed and wedge-shaped trailing edge: small-scale analysis and the `teapot effect' at large Reynolds numbers";
Journal of Fluid Mechanics, 926 (2021), A25; 52 pages.



English abstract:

Cover letter. This paper provides a fundamental theoretical understanding of the steady developed flow of a liquid Newtonian layer past an, initially sharp, trailing edge of a horizontal flat plate. The source of the forces at play are gravity in the vertical direction, surface tension and viscosity. The relevant Reynolds and Froude numbers are taken as arbitrarily large, whereas the Weber number of O(1) represents the crucial control parameter. Therefore, the methods of choice are matched asymptotic expansions, so as to deal adequately with the arising separation of scales, Fourier analysis and numerical tools used so solve the thereby reduced governing problems. The focus lies on the flow in the immediate vicinity of the plate edge, which finally requires its microscopic geometrical resolution. Highlights are the prediction of capillary ripples on the upper free surface upstream of the trailing edge and the fact that the underside of the plate is inevitably wetted. The last finding refers to a rational explanation of what is commonly referred to as the "teapot effect" when applied to a flow of relatively large momentum. On the smallest scales, this involves the formulation of one or two nested Stokes problems of free-surface type and entered by the wetting properties in terms of the static contact angle.


Keywords:
capillarity, contact angle, free-surface flows, Stokes flows, teapot effect, trailing edge, viscous-inviscid interaction


"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)
http://dx.doi.org/10.1017/jfm.2021.612

Electronic version of the publication:
https://publik.tuwien.ac.at/files/publik_296006.pdf


Created from the Publication Database of the Vienna University of Technology.